Volume overload (congestion) occurs in patients with heart failure (HF) and is the leading cause of hospitalization in the elderly worldwide. Unfortunately, clinical signs and symptoms; laboratory values; and existing diagnostic tools are unreliable in providing accurate assessment of volume status. Using a unique physiologic signal, Non-Invasive Venous waveform Analysis (NIVA), VoluMetrix has developed a proprietary device (?VasaWatch?) and algorithm designed for monitoring volume status in HF patients. Proof of concept data in humans and experimental animal models, demonstrate that VasaWatch provides a reliable indication of intravascular volume status. The studies in this Fast Track SBIR will establish that VasaWatch is a safe, sensitive, inexpensive method for non-invasive volume status monitoring in patients with HF.